Conventional car seats generally include a body with a recess defined in one side thereof and a retaining frame which generally is a U-shaped frame is pivotably connected to the car set so as to further retain the child in the car seat. The car seats are secured by safety belts of vehicles. The car seats usually are emphasized for its safety feature, tough material and side functions such as cup holders or even toys hanged on the retaining frames. However, all the existed car seats have a fixed size which cannot be adjusted along with different users. For children, they grow so fast that the car seats with a fixed size have to be replaced with larger ones and this costs a lot of money and how to discard the bulky car seats is a problem in some areas, such as the problem of the space for the trash and the pollution of environments.
The present invention intends to provide a seat that includes multiple retaining frames which are pivotably connected to the backrest and can be pivoted individually according to the users of different sizes.